Gallium/aluminum interdiffusion between n-GaN and sapphire

Abstract

The distribution profiles of Ga and Al near the interface of the n-GaN/sapphire system were measured by x-ray energy dispersive spectroscopy (XEDS). The results are obtained by the corrected XED spectra. First, the gallium diffusing into the sapphire substrate obeys the law of remainder probability function. The gallium diffusion coefficient DGa=2.30×10-13 cm2s-1 was calculated by theoretical fitting. Second, the diffusion is associated with the GaN growth process at high temperature. Compared to the diffusion of Ga into the sapphire substrate, much less Al antidiffusion from the substrate to the GaN film, with diffusion coefficient DA1 approximately equal to 4.8×10-15 cm2s-1, was observed in the film. © 1998 American Institute of Physics.